When Jack Sarfatti was 13 years old, he began receiving phone calls from a strange metallic voice that told him he would someday become part of an elite group of scientists exploring uncharted territory. Those calls, which he believes may have come from a computer on a spacecraft, proved a seminal influence on his life and led him to pursue a career that combined mainstream physics with an enduring interest in UFOs and the far-out reaches of science.

For those who might dismiss Sarfatti as a crank, he is quick to point out that he is not interested in debating the reality of little green men, but rather whether the existence of UFOs might prove that the technology required for interstellar travel is possible. “It’s the physics that interests me,” says Sarfatti, who received his PhD in the subject from the University of California.

That experience, and interest, also helped make Sarfatti one of the key figures invited last year to help formulate an unusual government programme: the 100-Year Starship (100YSS).

While the US government’s manned space programmes appear stuck in Earth’s orbit, this audacious project aims to kickstart efforts towards interstellar space travel – journeys over vast distances to stars outside of our solar system. It is driven by ideas that range from ensuring the survival of the human species and searching for intelligent alien life to the desire to overhaul space propulsion and just pure academic endeavor. Science fiction favourites from wormholes and warp drives to light speed and lasers are all on the table, meaning parts of the project can end up sounding like the wish list for an episode of Star Trek.

Stellar pipedream?

But the 100YSS is not a fringe activity started by a bunch of dreamers. It has the backing of two high-profile US agencies – the space agency Nasa and the Defense Advanced Research Projects Agency (Darpa), the US military agency that helped create the internet and satellite-based navigation. Darpa has a track record for these kinds of seemingly impossible technologies: in recent years it has sponsored attempts to develop a hypersonic aircraft and driverless cars.

But even those might pale next to the goal of sending a manned spaceship to the stars. And the agency’s willingness to embrace unconventional ideas and people – like Sarfatti – means the project divides opinion. For its backers it is a visionary blueprint for interstellar travel. For the naysayers, it is a crackpot idea with no hope of even getting off the ground.

For those who might consider a starship something of a pipedream, David Neyland, the head of the Darpa office in charge of the 100YSS, points to the agency’s ability to spur innovation in unexpected areas, an ability that has proven critical to its success. “The iPhone in your pocket is powered by cellular radio technology that came out of communications research Darpa did back in the 70s and 80s,” says Neyland. “So it is that unintended consequence of technology research that we are hoping to inspire.”

Of course, when it comes to spaceships, we have been here before. Serious study of interstellar travel has long attracted a coterie of dedicated followers spanning mainstream science and the outer fringes. Wernher von Braun, the famous rocket scientist, justified his work on military weapons as a way to further engineering that would lead mankind to space. “I aim at the stars, but sometimes I hit London,” became a satirical jab at von Braun, whose dreams of travel to Mars led him to build the V2 rockets for Nazi Germany that rained down on England during World War II.

Interest also grew in novel propulsion methods, driven in part by the idea that conventional rocket technology was just too slow to mount even a one-way trip to our closest stellar neighbour, Alpha Centauri. Some estimates suggested it would take at least 80,000 years to travel the four light-years there, requiring multi-generation spaceflight and fuel demands that do not bear thinking about.

Hence, interest grew in technologies such as solar sails, blown along by streams of light particles. In the 1980s, physicist Robert L Forward even proposed a solar sail driven by a giant laser, which would push a spaceship at close to the speed of light (although some consider even that technology too slow for interstellar exploration).

Risky thinking

Writing about those ideas is one thing, but building them is another, says Mark Lewis, a professor of aerospace engineering at the University of Maryland and a former US Air Force chief scientist. The laser-powered light sail, for example, would require planet-sized optics as big as Jupiter. “One can write the equations to demonstrate how it would be done, but the resources needed to actually build it would be enormous,” he says. “We know how to build them, but that doesn’t mean we could.”

Nearly three decades later, Forward’s laser-powered light sail – as well as other ideas for interstellar travel – are still popular among space enthusiasts and science fiction writers, but they have gained little traction by way of funding or serious progress. In the 1990s Nasa briefly supported the Breakthrough Propulsion Physics programme, which funded scientific research in areas such as rocketless space drives and faster-than-light travel. However, that program lost its funding in 2002.

Advancing these ideas, say experts, would require decades of research and billions of dollars, something that a government, particularly in a time of austerity, is unlikely to do. “Right now the established aerospace community is reaching a stagnation point; it is trying to finish what was started in ‘60s, rather than adapt,” said Mark Millis, a former Nasa scientist who headed the Breakthrough Propulsion Physics programme.

Millis, who left Nasa in 2010, now dedicates his time to the Tau Zero Foundation, an Ohio-based nonprofit he started to help further interstellar travel. “I tried to keep doing cool, futuristic stuff, but it’s just not going to happen in government,” he said of his decision to leave Nasa. “I realized I’m going to have to go independent.”

Ironically, that same thinking is what motivated Darpa and Nasa to start the 100YSS. Neyland, the Darpa official, says the idea for the project came out of a meeting he had with the head of Nasa’s Ames Research Center, Pete Worden, who has a reputation as an out-of-the-box thinker willing to take risks.

“What we realised right off was that if you look at history, any major exploration, like crossing the oceans, crossing the continents, building telescopes for looking into space, those things have always been done outside of government circles,” said Neyland last year. “They’ve been funded by patrons or non-government organisations.”

Their idea was to do for interstellar travel what the Medici court did for Galileo: provide long-term funding to encourage scientific breakthroughs.

In January 2011, Darpa and Nasa convened a handful of people, including Sarfatti, to help shape the project. It was decided that the government would provide a modest seed fund of just $500,000 – a drop in the ocean compared to Darpa’s annual budget of about $3 billion – to a foundation that could demonstrate its ability to advance thinking on interstellar travel. Darpa believes the chosen group will then find new sources of revenue, either through commercialising technologies or private donations. And, of course, if there are a few spin-off technologies that Darpa – whose main customer is the US Department of Defense – can exploit, then all the better.

The 100-years part, according to Neyland, was merely an estimate of how long it would take to really move such an ambitious project forward.

“If you even look at our own space programme, if you look at how far we’ve come, it’s been 41 years since we first landed on the moon,” he said. “So we thought a 100-year time horizon, not for the study, but 100 years of doing research and development, gave us some practicality of developing technologies that we couldn’t foresee today.”

The idea of a suicide mission was not quite what the two agencies had in mind.

Nasa has since stepped back, allowing Darpa – which has even hired a public relations firm to handle publicity for the project – to take the lead. Despite that initial misstep, a conference open to the public held late last year proved popular. At a panel on breakthrough propulsion, an audience eager to hear about warp drive and faster-than-light travel spilled out of the room and into the hallway.

And no wonder, since many of the ideas sounded like they had come straight out of a Hollywood script for going where no man has gone before. Sarfatti proposed a low-power warp drive (a faster-than light propulsion system) that involves the warping of spacetime around the starship. His idea involves using new meta-materials – which change how light is refracted – to slow the speed of light, while also creating a repulsive anti-gravity effect, creating a warp bubble surrounding the starship. This approach, Sarfatti anticipates, would break the space-time barrier, allowing the spaceship to travel beyond the speed of light in its own bubble. (A related Sarfatti proposal involves using a “quantum entanglement communicator”, which would allow the ship’s crew to speak with people back on Earth).

Eric W Davis, a physicist at the Texas-based Institute for Advanced Studies at Austin, an independent think tank, proposed a traversable wormhole, which would provide a hyperspace shortcut for a spaceship travelling to the stars. The idea would be to harness the energy found in free space - known as negative vacuum energy - to shape the wormhole, allowing the spaceship to travel to Alpha Centauri in just a few days. The difficulty, however, is producing enough negative vacuum energy to create the wormhole.

The symposium also covered the ethical, medical, and even religious aspects of interstellar space travel. Adam Crowl, a board member of Project Icarus, an organisation dedicated to interstellar travel, proposed a possible “escape” mission for a spaceship to ensure mankind’s survival in case of a catastrophe on Earth. His proposal, with echoes of sci-fi like Battlestar Gallactica and Wall-E, involved sending embryos into space to be raised by androids. “It’s a theoretical exercise in looking at the risks to humanity from our own inventions,” he says. “What we might do is to provide a fallback option.”

Those who align themselves with 100YSS are well aware that talk of spacebound embryos and breaking the space-time barrier is open to ridicule. And at events like the symposium, there are efforts to keep discussion away from what many consider to be overly outlandish topics, like UFOs.

The project has also tried to raise its credibility by including a range of skeptics, particularly on the propulsion ideas. Ken Olum, a physicist at Tufts University in Boston, who took part in a breakthrough propulsion panel at the Darpa symposium, says that schemes like wormholes and warp drive are interesting to discuss but they just are not practical: no one has any clue how to build them.

“Even though I think that there’s not likely to be much future in exotic stuff, like wormholes, I think a little bit of funding should be given to them,” he says. “But they are not the answer to the problem of what we will do in the next 100 years to go to the stars.”

But Levit, the Nasa scientist, says these sorts of breakthrough propulsion ideas, however far-fetched, have to be considered, because they are the only way mankind could conceivably cover the vast distances to other stars.

“Nuclear fusion, if you’re willing to have a 1,000 year mission, is worth talking about,” says Levit, although even this is also an unproven technology, despite decades of effort on Earth.

“But I tend to agree with Jack [Sarfatti] on this: in order to do this, we have to have a breakthrough. We have to have a warp drive.”

Levit, who was the one who invited Sarfatti to the initial 100-Year Starship meeting, says unusual interests shouldn’t make someone off-limits. Mainstream scientists are tied down, argues Levit, and someone like Sarfatti is free to talk about ideas like antigravity propulsion without fear of repercussions on his career. “Although his interests and style are outside of the mainstream, he is a fully pedigreed physicist and he knows as much or more than mainstream physicists,” Levit says. “When he talks about warp drives, he knows what he’s talking about. He knows he’s speculating.”

In December 2011, Darpa selected a team led by Mae Jemison, the first African-American woman to travel to space, as the winner of a $500,000 grant. Jemison, whose partners included the Icarus Foundation and the Foundation for Enterprise Development, won with a proposal called An Inclusive, Audacious Journey Transforms Life Here on Earth and Beyond.

While details of what Jemison and her team intend to do are unclear, the news could spell the death of another interstellar travel foundation. Millis, the head of the Tau Zero Foundation, said that he would have to consider shutting down his operations. “There are not enough revenues around to try to compete,” he says. “I think that would be a disservice to the community.

Sarfatti sees it differently. After spending most of his career as an outsider pursuing faster-than-light travel, he is undaunted by the arrival of a government-backed competitor. Instead, he has shunned the 100YSS process and plans to continue work on his warp drive independently. The Darpa project, he say, is simply too little money to be taken seriously. “I am in touch with people with considerable resources,” he says. “I’ll do it on my own and do what I want to do.”